A Brief History of Protein: Passion, Social Bigotry, Rats, and EnlightenmentBy: John McDougall M.D.www.drmcdougall.com

Nutrition is an emotional subject and nothing arouses
people’s passions more than the subject of protein in their diet. Widely
divergent opinions on whether more protein or less is best, and on the
merits of animal vs. vegetable sources, have been debated for more than
150 years. And for all that time solid scientific research has clearly
supported the wisdom of a diet low in protein – favoring vegetable
sources. So far, however, the scientific facts have fought a losing
battle against popular opinion – which values high-protein diets based
on animal foods. Mark Twain once said, “Truth is mighty and will
prevail. There is nothing wrong with this, except that it ain't so.”
Even though the facts may never become popular knowledge, I will always
believe it is your fundamental right to know the truth about your
nutritional requirements – this vital information should be taught from
childhood as basic education, along with reading, writing, and
mathematics – and along with health facts such as cigarettes cause lung
damage, drunk driving kills, and automobile safety belts save lives.

High Protein Standard Set by Social Bigotry

One of the earliest proponents of high protein diets
was the distinguished German physiologist Dr. Carl Voit (1831-1908).1,2
After studying laborers who consumed approximately 3100 Calories daily,
he concluded that protein intake for people should be 118 grams (g) per
day – this value became known as the “Voit standard.” How did he reach
this conclusion? He believed that people with sufficient income to
afford almost any choice of foods – from meat to vegetables – would
instinctively select a diet containing the right amount of protein to
maintain health and productivity. Other European and American
authorities made similar observations about the eating habits of working
men with sufficient incomes to afford meat and came to similar
conclusions – ultimately recommending diets high in protein (100 and 189
grams of protein a day). No experiments were performed on the human body
to reach these conclusions. Information on the diets of vigorous
individuals living during these times and following low-protein
vegetarian diets was largely ignored.2,3 The healthy active lives of
hundreds of millions of less affluent people laboring in Asia, Africa,
and Central and South America on diets with less than half the amount of
protein recommended by Dr. Voit (and almost no meat), were overlooked
when experts established protein requirements that still affect us
today.3,4

What arrogance! To conclude that the superior
intellect of moderately affluent people of European descent would cause
them to naturally come to correct conclusions about their personal
nutritional needs. What foolishness! You can see the effects of
self-selection when unrestricted food choices are available. What do
more than one billion people living in the 21st century choose?
McDonald’s, Burger King, Pizza Hut – need more be said about people’s
innate wisdom to make food selections in their best interests?
Unfortunately, these flawed recommendations based upon such social
bigotry have not yet been silenced by over 100 years of scientific
research.

Russell Henry Chittenden Tells the Truth a Century
Ago

Such narrow-minded thinking should have been stopped
by 1905 when Russell Henry Chittenden, Yale University Professor of
Physiological Chemistry, published his scientific findings on human
protein needs in his classic book, Physiological Economy in Nutrition.2
Professor Chittenden believed Dr. Voit had cause and effect reversed:
people did not become prosperous because they ate high protein diets,
but rather they ate meat and other expensive high protein foods because
they could afford them. One hundred years ago he wrote, “We are all
creatures of habit, and our palates are pleasantly excited by the rich
animal foods with their high content of proteid (protein), and we may
well question whether our dietetic habits are not based more upon the
dictates of our palates than upon scientific reasoning or true
physiological needs.”

He reasoned that we should know the minimal protein
requirement for the healthy man (and woman), and believed that any
protein intake beyond our requirements could cause injury to our body,
especially to the liver and kidneys. As he explained it, “Fats and
carbohydrates when oxidized in the body are ultimately burned to simple
gaseous products…easily and quickly eliminated...” “With proteid
(protein) foods…when oxidized, (they) yield a row of crystalline
nitrogenous products which ultimately pass out of the body through the
kidneys. (These nitrogen-based protein byproducts) – frequently spoken
of as toxins – float about through the body and may exercise more or
less of a deleterious influence upon the system, or, being temporarily
deposited, may exert some specific or local influence that calls for
their speedy removal.” With these few words Professor Chittenden
explained the deleterious effects of diets high in protein and meat –
consequences too few practicing doctors know about today.

The First Scientific Experiments on Our Protein
Needs

Professor Chittenden’s first experiment was on
himself. For nine months, he recorded his own body weight, which
decreased from 143 pounds (65 Kg) to 128 pounds (58 kg) on his new diet
of one-third the protein that Dr. Voit recommended. Chittenden's health
remained excellent and he described his condition as being with “greater
freedom from fatigue and muscular soreness than in previous years of a
fuller dietary.” He had suffered from arthritis of his knee and
discovered that by reducing his intake of meat his condition disappeared
and his “sick headaches” and bilious attacks (abdominal pains) no longer
appeared periodically as before; plus he fully maintained his mental and
physical activity, with a protein intake of about 40 grams a day.

Chittenden performed valid scientific studies by
collecting data on the daily dietary and urine histories of his subjects
(including himself) to determine protein utilization. Because he was
contradicting the known “truths” of his time, he proceeded with extreme
caution with his further investigations. He organized three controlled
trials with increasing demands for testing the adequacy of diets lower
in protein than commonly recommended.

The first trial involved a group of five men connected
with Yale University, leading active lives but not engaged in very
muscular work. On a low-protein diet (62 grams daily) for 6 months, they
all remained healthy and in positive nitrogen balance (more protein went
into, than out of, their bodies). The second trial used 13 male
volunteers from the Hospital Corps of the U.S. army. They were described
as doing moderate work with one day of vigorous activity at the
gymnasium. They remained in good health on 61 grams of protein daily.
His final trial was with 8 Yale student athletes, some of them with
exceptional records of athletic events. They ate an average of 64 grams
of protein daily while maintaining their athletic endeavors, and
improving their performance by a striking 35 percent. Following these
studies, Chittenden in 1904 concluded that 35–50 g of protein a day was
adequate for adults, and individuals could maintain their health and
fitness on this amount. Studies over the past century have consistently
confirmed Professor Chittenden’s findings, yet you would hardly know it
with the present day popularity of high protein diets.

Rats Confuse Nutritionists

Many people have the idea that animal foods contain
protein which is superior in quality to the protein found in plants.
This misconception dates back to l9l4, when Lafayette B. Mendel and
Thomas B. Osborne studied the protein requirements of laboratory rats
and demonstrated nutritional requirements for the individual amino
acids.5 They found that rats grew better on animal sources of protein
than on vegetable sources. So, investigators at that time suspected that
the vegetable foods had insufficient amounts of some of the amino acids
essential for the normal growth of rats. Because of these and other
animal-based experiments, flesh, eggs, and dairy foods were classified
as superior, or "Class A" protein sources. Vegetable proteins were
designated inferior, or "Class B" proteins.

Studies completed in the early 1940's by Dr. William
Rose of the University of Illinois found that l0 amino acids were
essential for a rat’s diet.6 The removal of any one of these essential
amino acids from the food of growing rats led to profound nutritive
failure, accompanied by a rapid decline in weight, loss of appetite, and
eventually death. Animal products, such as meat, poultry, milk, and eggs
prevented this decline in the rats’ health, and were found to contain
the l0 essential amino acids in just the right proportions for needs of
growing rats. Based on these early rat experiments the amino acid
pattern found in animal products was declared to be the “gold standard”
by which to compare the amino acid pattern of vegetable foods. According
to this concept, wheat and rice were declared deficient in lysine and
corn was deficient in tryptophan.

Subsequent research has shown the obvious: the initial
premise, that animal products supply the most ideal protein pattern for
humans, as they do for rats, is incorrect.7 The dietary needs of rats
are considerably different from those of humans, mainly because rats
grow very rapidly into adult size as compared to people. Rats are fully
adult after 6 months; whereas a person takes 17 years to fully mature.
This difference in need is especially clear when the breast milk of both
species is examined and compared. The protein content of rat breast milk
is 10 times greater than the milk intended for human babies.8,9 Baby
rats double in size in 4.5 days; an infant doubles in size in 6 months.
The obvious reason for the different needs is because rats grow very
rapidly into adult size as compared to humans; therefore requirements
for protein to support that growth are very much higher.

Dr. William Rose Discovers Human Needs

In 1942, Dr. William Rose turned his attention from
rats to people and began studying the amino acid requirements for humans
using basically the same methodology he had used with rats. Healthy,
male graduate students, grateful in those days for the free food, the
dollar a day they were paid and the prospect of getting their initials
in print in Rose's widely read publications, served as his experimental
animals. They were fed a diet consisting of corn starch, sucrose, butter
fat without protein, corn oil, inorganic salts, the known vitamins, and
mixtures of highly purified amino acids. Their diet also included a
large brown "candy," which contained a concentrated liver extract to
supply unknown vitamins, sugar, and peppermint oil to provide a
"never-to-be-forgotten taste."

The study used a chemical measurement called nitrogen
balance to determine whether the subjects were getting enough usable
protein from the mixture. From his experiments, Dr. Rose found that only
eight of the ten amino acids essential to rats were also essential to
men – we were better at making two amino acids than rats. When an
essential amino acid was given in insufficient amounts for approximately
two days, all subjects complained bitterly of similar symptoms: a clear
increase in nervous irritability, extreme fatigue, and a profound
failure of appetite. The subjects were unable to continue the amino acid
deficient diets for more than a few days at a time.

Through his studies, Dr. Rose also determined a
minimum level of intake for each of the eight essential amino acids.10
He found small amounts of variation in individual needs among his
subjects. Because of these unexplained differences among people, he
included a large margin of safety in his final conclusion on minimum
amino acid requirements. For each amino acid, he took the highest
recorded level of need in any subject, and then doubled that amount for
a "recommended requirement" – described as a definitely safe intake. It
is important to realize that his higher requirement is easily met by a
diet centered around any single starchy vegetable. Even in children, as
long as energy needs are satisfied by starch, protein needs are
automatically satisfied in almost every situation because of the basic
and complete design of the food. These investigations were completed by
the spring of 1952, resulting in sixteen papers in The Journal of
Biological Chemistry that are considered classic contributions in the
history of nutrition for the benefit of human beings.

The results of Dr. Rose`s studies are summarized in
the following chart, under "minimum requirements". From the chart, it is
clear that vegetable foods contain more than enough of all the amino
acids essential for humans.11

Many investigators have measured the capacity of plant foods to meet
our protein needs. Their findings show that children and adults thrive
on diets based on a single starch; and they grow healthy and
strong.11,12 Furthermore, no improvement is obtained by mixing plant
foods or supplementing with amino acid mixtures to make the combined
amino acid pattern look more like that of flesh, dairy, or eggs.12 (For
a thorough discussion of human protein needs see The McDougall Plan, New
Win Publishers.)

Diet for a Small Planet Helps and Harms

A popular book among vegetarians, Diet for a Small Planet, by Frances
Moore Lappe’ published in 1971, started a revolution that has had a
positive impact for the past three decades on the lives of millions of
people. Unfortunately, Ms. Lappe’ failed to understand the basic
scientific literature on human protein needs and the sufficiency of
plants foods before she wrote her influential book. She believed plants
contained “incomplete proteins” with insufficient amounts of certain
essential amino acids to meet the needs of people.13 As a result of this
misunderstanding, she placed great emphasis on combining vegetable foods
to create an amino acid pattern which resembles that found in animal
foods. This emphasis is unnecessary and implies that it is difficult to
obtain “complete” protein from vegetables without detailed nutritional
knowledge. Because of her complicated and incorrect ideas people are
frightened away from vegetable-based diets.

The impact of her incorrect teachings of more than 30 years ago
affects nutritional policy even today. In 2001 the Nutrition Committee
of the American Heart Association published a long overdue review
warning people of the dangers of high protein diets, like the Atkins,
the Zone, and Sugar Busters diets.14 Unfortunately, this one statement
in an otherwise valuable report is scientifically incorrect: “Although
plant proteins form a large part of the human diet, most are deficient
in 1 or more essential amino acids and are therefore regarded as
incomplete proteins.” For a supporting scientific reference the
Committee cites Frances Moore Lappe’s 1971 book, Diet for a Small
Planet.

You may think this is a trivial matter; however, incorrect
information on our protein needs can have grave consequences on your
health and your family’s health. With the American Heart Association
teaching that plants fail to supply complete protein you are almost
certain to receive incorrect, potentially damaging, medical advice. For
example, say you go to your doctor after a heart attack and mention that
you are now going to become a pure vegetarian to avoid future heart
trouble. Your doctor may respond, “You can’t do that, you will become
protein deficient on an all plant food diet – the Heart Association says
so.” Or your child is sick with recurrent asthma and ear infections and
you want a dietary cure – you may be warned away from a highly effective
therapy because members of the Nutrition Committee of the American Heart
Association fail to understand basic scientific research about human
protein needs and plant foods. So this is no small matter.

I have confronted the Heart Association about spreading
misinformation that can result in suffering as serious as death from
heart disease – so far they have shown no interest in making overdue
corrections to their incorrect teaching. (See my July, August and
November 2002 Newsletters for more information on this.) I recently
shared my conflict with the Heart Association with the world’s leading
authority on human protein requirements, Dr. D. Joe Millward from the
Center for Nutrition and Food Safety, School of Biological Sciences
University of Surrey, UK. His response to me on July 10, 2003 was,
“Contrary to general opinion, the distinction between dietary protein
sources in terms of the nutritional superiority of animal over plant
proteins is much more difficult to demonstrate and less relevant in
human nutrition. This is quite distinct from the AHA position which in
my view is wrong.” 15

So How Do You Know the Truth about Your Protein Needs?

Read the scientific literature
www.nlm.nih.gov and look at the
world picture. Notice that 60 percent of people alive today and most of
the people who have lived in the past have obtained their protein from
plant foods. They have lived successfully; avoiding all the diseases
common in our society. Even today plant sources provide 65% of the world
supply of the protein we eat.

What about the starving children in Africa? The picture one often
sees of “protein deficient” children in famine areas of Asia or Africa
is actually one of starvation and is more accurately described as
“calorie deficiency.”11 When these children come under medical
supervision, they are nourished back to health with their local diets of
corn, wheat, rice, and/or beans. Children recovering from starvation
grow up to l8 times faster than usual and require a higher protein
content to provide for their catch-up in development – and plant foods
easily provide this extra amount of protein. Even very-low protein
starchy root crops, such as casava root, are sufficient enough in
nutrients, including protein, to keep people healthy.3

The World Health Organization knows the truth. Since 1974 it has
recommended that adults consume a diet with 5% of the calories from
protein – this would mean 38 grams of protein for a man burning 3000
calories a day and 29 grams for a woman using 2300 calories a day. These
minimum requirements provide for a large margin of safety that easily
covers people who theoretically could have greater protein needs – such
as accident victims or people with infections. This quantity of protein
is almost impossible to avoid if enough whole plant food is consumed to
meet daily calorie needs. For example, rice alone would provide 71 grams
of highly useable protein and white potatoes would provide 64 grams of
protein for a working man.16 For a pregnant woman the WHO recommends 6%
of the calories come from protein – again an amount of protein easily
provided by a diet based on starches, vegetables, and fruits.

Human Breast Milk – Your Final Assurance

Your greatest need for protein is when you grow the
most. The greatest time of growth in a human being’s life is as an
infant. We double in size during the first 6 months. The ideal food for
a baby is mother’s milk. Therefore, breast milk is the “gold standard”
for nutrition – during your time of greatest need for all nutrients,
including protein. Five to 6.3 percent of the calories in human breast
milk are from protein.9,17 This is the maximum concentration of protein
we will ever need in our food supply. Knowing this value tells us that
at no other time in our life will we ever require more protein. Consider
the protein content of the foods we consume after weaning – these are
even higher in protein – rice is 9%, potatoes are 8%, corn is 11% and
oatmeal is 15% protein.16

Wrong Thinking Ruins Health

Even though all the scientific knowledge accumulated
over the past 100 years clearly shows our bodies were designed to live
best on a diet lower in protein than dictated by common belief, we
continue on the same disastrous dietary path. As Russell Henry
Chittenden explained 100 years ago, “The poorer man emulates his richer
neighbors as soon as his circumstances permit, and resources that could
be much more advantageously expended for the good of the family and the
home are practically wasted – to say nothing of possible injury to
health – under the mistaken idea that this more generous method of
living (a high-protein, high-meat diet) is the surest road to health and
strength.”2 Dr. Chittenden also believed that knowledge and the truth
would prevail. He wrote, “Habit and sentiment play such a part in our
lives that it is too much to expect any sudden change in custom. By a
proper education commenced early in life it may, however, be possible to
establish new standards, which in time may prevail and eventually lead
to more enlightened methods of living...” The past century of declining
health for people living in developed countries has proved Chittenden
wrong – so far. However, with widespread communication via the Internet
his predictions may soon become reality.

References:

1) Carpenter K. A short history of nutritional
science: part 2 (1885-1912). J Nutr. 2003 Apr;133(4):975-84.

2) Chittenden, R. H. (1904). Physiological economy in
nutrition, with special reference to the minimal protein requirement of
the healthy man. An experimental study. New York: Frederick A. Stokes
Company.

14) St. Jeor S, Howard B, Prewitt E. Dietary protein
and weight reduction. A statement for health professionals from the
Nutrition Committee of the Council on Nutrition, Physical Activity, and
Metabolism of the American Heart Association. Circulation
2001;104:1869-74.

The Meat Free Zone (MFZ) campaign is intended to make the MeatFreeZone logo as
recognizable a symbol as the "Smoke Free Zone". The idea was originally
conceived when The WARM Store in Woodstock, NY, was in operation throughout the
'90's (Woodstock Animal Rights Movement). The store was truly a meat free zone
as it was the first cruelty-free, Vegan, socially conscious animal rights store
in the United States. Now that the Vegan and Vegetarian movements have been
growing so rapidly, more and more people are showing concern about the food in
their diet and their overall health and nutrition. Many people are giving up
eating fish, chicken, beef, pork (pigs ), dairy (milk, cheese, yogurt,
ice cream) and eggs. Headlines of Mad Cow disease, E-coli
and salmonella are in the news with greater frequency. Vegan and vegetarian
recipe cookbooks are standard now in all bookstores and many restaurants have
added Vegan and Vegetarian options to their menus. We hope you will help us with
the Meat Free Zone campaign by putting the signs up in your homes and workplaces
and by spreading them to all the vegetarian and vegan restaurants that you know
and frequent. And someday we will have true "meat free zones" in establishments
that serve meat.
(d-4)